[ns] How to set the timeout and packet size for a TCP agent

[Huan Pham <huan@cs.jcu.edu.au>]

Hi NS users,

In my simulation, it looks as TCP uses its default timeout value of a
couple seconds. So my first question is how to change that default
value?

Q1 - How to set the time-out value for a TCP agent

I am now simulating an Exponential traffic source with the packet size
of 200 bytes, running on top of TCP. By default TCP uses packet size of
1000 bytes. My simulation results look as if TCP use the whole packet
size of 1000 bytes to carry only one Application data of 200 bytes!
That's unacceptable.

As a result, I have to explicitly set:

$tcp_agent set packetSize 200

and it works fine: each TCP packet (of 200bytes) carries one Application
data packet.

My question is:

Q2 - Is there a way for TCP agent to automatically learn Application
traffic data size, and use this value instead of its default 1000 byte
packets?

Q3 - Is there a way (and is it feasible in practice or not)  that TCP
groups a couple of small application data packets to make a bigger
packet before transmission?

Your help would be greatly appreciated.

Thanks in advance.

Huan Pham